1. Field of the Invention
A power steering assembly for a vehicle to assist in steering a vehicle.
2. Description of the Prior Art
Typically, a power steering system involves a hydraulic system. The hydraulic system requires several components, which mainly include a power steering pump for pressurizing fluid and a control valve. A steering wheel is connected to the control valve such that rotation of the steering wheel rotates the control valve. The control valve directs the pressurized fluid from the pump into a side of a piston to assist the driver in turning steerable wheels of a vehicle. These hydraulic systems require heavy components and are an additional inefficiency to the engine due to the power demands of the power steering pump. However, the hydraulic system is well known in the art and advanced systems with variable power assistance and advance controllers are widely used in vehicles today.
Another power steering system, such as the one disclosed in U.S. Pat. No. 6,991,573, utilizes an electric motor to provide assistance to turn the steerable wheels of the vehicle. The electric motor rotates a motor shaft at high speed and is geared down through a gear train that converts the rotational motion of the motor shaft into a linear advance that aids the driver to move the steerable wheels. The conversion of the rotary motion of the electric motor into a linear movement creates backlash and adds additional inertia and frictional inefficiency to the power steering system. In particular, to change direction of the linear movement requires the electric motor, which can be rotating in one direction, to stop and rotate in an opposite direction. The inertia of the electric motor, as well as the remaining components of the power steering system, can be substantial and can introduce a variety of inefficiencies into the system.
Therefore, it is desirable to design a power steering system that does not require a conversional gear train from a rotary movement into a linear movement, compatible with power restraints of electric or hybrid vehicles and does not require additional components such as a power steering pump or an electric motor to assist the driver in moving the steerable wheels.